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### De Broglie Equation

Posted: Fri Nov 02, 2018 7:58 pm
A baseball must weigh between 5.00 and 5.25 ounces (1 ounce 28.3 g). What is the wavelength of a 5.15-ounce baseball thrown at 92 mph?

When solving for this, why do we use the De Broglie Equation to calculate wavelength?

### Re: De Broglie Equation

Posted: Fri Nov 02, 2018 8:15 pm
De Broglie basically was saying that all objects in our world have a wavelength, but that the more massive the object, the smaller the wavelength. Essentially we can only observe the wavelengths of an object when it's tiny enough (ie an electron or atom). So when we're talking about a baseball and we're given a mass and a velocity, and asked to find a wavelength, we can use the de broglie equation (wavelength= planck's constant/(mass x velocity) ) to get the value we need. Honestly I've noticed that when questions ask for the wavelength of everyday objects (i.e. baseballs ) they're usually trying to ask for de broglie, so that's my tip off to try and see if the DB equation would help me. Hope that helped!

### Re: De Broglie Equation

Posted: Fri Nov 02, 2018 8:44 pm
You use De Broglie's equation for everything with mass (electron, proton, everyday objects). You use E=hv for a photon because it has no resting mass.